The purpose of this project is to study the regulation of gonadotropin receptors, adenylate cyclase and protein kinase activities in the rat ovaries and porcine granulosa cells. The gonadotropin-induced acute loss of LH- and FSH- receptors will be investigated in vivo and in vitro and correlated with desensitization of adenylate cyclase. The relationship between LH binding and activation of LH-sensitive adenylate cyclase will be determined during the induction and disappearance of the LH receptors. The role of luteotrophic and luteolytic hormones on the regulation of gonadotropin receptors, cyclic AMP and cyclic GMP levels, adenylate cyclase and protein kinase activities will be established. The intraovarian regulation of granulosa and luteal cells by follicular fluid inhibitor and LH receptor binding inhibitor will be explored and the mechanism of inhibitory action will be investigated.